Measuring Macroeconomic Tail Risk∗
Roberto Marf`e† Julien P´enasse‡
This draft: July 27, 2021
Abstract This paper proposes a predictive approach to estimate macroeconomic tail risk dynamics over the long run (1876-2015). Our approach circumvents the scarcity of large macroeconomic crises by using observable predictive variables in a large international panel. This method does not require asset price information, which allows us to evaluate the empirical validity of rare disasters models. Our macro risk estimates covary with asset prices and forecast future stock returns, in line with the prediction that macroeconomic tail risk drives the equity premium. A rare disaster model, calibrated from macroeconomic data alone, further supports this interpretation. JEL: E44, G12, G17 Keywords: rare disasters, equity premium, return predictability
∗A previous version of this paper was titled “The Time-Varying Risk of Macroeconomic Disasters.” We thank Daniel Andrei, Patrick Augustin, Bo Becker, Jules van Binsbergen, Pierre Collin-Dufresne, George Con- stantinides, Max Croce, Magnus Dahlquist, Darell Duffie, Leland Farmer, Xavier Gabaix, Anisha Ghosh, Eric Ghysels, Anisha Ghosh, Fran¸coisGourio, Daniel Greenwald, Robin Greenwood, Benjamin Holcblat, Hendrik H¨ulsbusch, Christian Julliard, Leonid Kogan, Peter Kondor, Christos Koulovatianos, Hening Liu, Andr´eLucas, Sydney Ludvigson, Rajnish Mehra, Christoph Meinerding, Alan Moreira, Tyler Muir, Stijn Van Nieuwerburgh, Marcus Opp, Riccardo Sabbatucci, Urszula Szczerbowicz, Adrien Verdelhan, Emil Verner, Tan Wang, Michael Weber, R¨udigerWeber, and Irina Zviadadze for helpful comments. We also benefitted from useful comments by conference and seminar participants at the Columbia University Macro Lunch, U. of Luxembourg, U. of Chile, Funda¸c˜aoGet´ulioVargas (Rio), McGill University, Stockholm School of Economics, and conference participants at the CEPR ESSFM Gerzensee 2017 meeting, SAFE Asset Pricing Workshop 2017, NFA 2017, Paris December 2017 Finance Meeting, the MFA 2018, and the EFA 2020. †Collegio Carlo Alberto, Piazza Arbarello, 8, 10122 Torino, Italy; +39 (011) 670-5229; [email protected], http://robertomarfe.altervista.org/ ‡University of Luxembourg, 6, rue Richard Coudenhove-Kalergi L-1359 Luxembourg, Luxembourg; +352 466644 5824; [email protected], https://sites.google.com/view/jpenasse Many puzzles in macro-finance arise from the inability of models to reconcile, quantitatively, asset prices and macroeconomic risk. A classic example is the equity premium puzzle: averaged stock returns are far too high to be explained by the observed risk in consumption (Mehra and Prescott, 1985). Another well-known example is that valuation ratios, such as the dividend-price ratio, can forecast stock returns (Campbell and Shiller 1988b). Likewise, stock market volatility is too high to reflect forecasts of future dividends (Shiller, 1981). A potential resolution of these puzzles is that we do not observe the risk that agents genuinely care about. Rare disaster models (Rietz, 1988; Barro, 2006), in particular, posit that agents care about infrequent but severe macroeconomic crises. Gabaix(2012), Gourio(2012), and Wachter(2013) show theoretically that variation in macroeconomic tail risk can rationalize the above puzzles. Unfortunately, the success of rare disaster models relies on an elusive state variable: the time-varying probability of a large macroeconomic crisis. The apparent difficulty in measuring macroeconomic tail risk has created controversy over whether rare disaster models are falsifiable.1 In this paper, we propose a straightforward method to estimate time-varying disaster prob- abilities based on predictive regressions. Our approach does not require asset price information and can be deployed over a very long timeframe. It circumvents the scarcity of large macroe- conomic crises by exploiting the informational content of variables that forecast such crises and, in the spirit of Barro(2006), by using a broad cross-section of countries. Our measure of disaster risk allows us to document for the first time that stock prices actually respond to macroeconomic tail risk—arguably the main testable prediction of rare disaster models. Concretely, we set up a probit panel model where the left-hand-side variable is an indicator equal to one when a given country i experiences a large macroeconomic crisis in year t + 1, and zero otherwise. Our international panel builds on Barro and Urs´ua(2008) and covers 1876 to 2015, comprising 42 countries. Our baseline specification defines a macroeconomic crisis as a two-standard-deviation drop in consumption below its long-term growth path in a given year. On the right-hand side of our forecasting model, we consider a rich set of time-t predictor variables, including macroeconomic variables such as realized crises at home and abroad, but also wars, political crises, natural disasters, and (potentially) asset prices. The fitted values in this regression yield the time-t probability of a macroeconomic crisis in country i in year t + 1. Figure1 gives an overview of our main result. It shows the next-year probability of a macroeconomic crisis in the United States. The probability, which we denote byπ, ˆ mostly varies between 0% and 10%, with higher levels during the Depression of 1893, the Great Depression, the two world wars, and the Great Recession of 2009. Our forecasting model performs remarkably
1For instance, John Campbell referred to the probability of rare disasters as economists’ “dark matter” in his 2008 Princeton Lectures in Finance (Campbell, 2017).
1 well out-of-sample and could, therefore, be used to predict crises in real-time. The most reliable predictors include realized crises at home and in neighboring countries, wars, and the U.S. (or world) dividend-price ratio. Our macroeconomic tail risk (or macro risk, for short) estimates are remarkably insensitive to the sample period and econometric specification. Probit coefficients are broadly stable over time and between advanced and emerging countries. Changing the crisis cutoff to 1.5, 2.5, and 3 standard deviations or using the crises identified in Barro and Urs´ua (2008) also produce qualitatively similar results. Under the condition that our predictor set approximately spans the information set of eco- nomic agents,π ˆ can be interpreted as the rational expectation probability of a large macroe- conomic crisis. It thus provides a benchmark with which to evaluate theories where tail risk plays a role. In the second part of the paper, we ask whether macro risk is related to the equity premium. We find that asset prices tend to be low (high dividend-price ratio) whenπ ˆ is high (corr. = 0.50). By itself, the U.S. dividend-price ratio—a standard equity premium proxy in the literature (e.g., van Binsbergen and Koijen, 2010)—captures a lot of information about future crises. A one standard deviation increase in the D/P ratio raises the likelihood of a crisis by 2.1 percent, which is about half the unconditional crisis probability of 3.9%. This is precisely what one would expect if investors were shunning stocks when tail risk is high, as predicted by rare disasters models. We find similar results using the equity premium proxy proposed by Martin (2017). Furthermore, macro risk directly forecasts international stock returns, further confirm- ing the link between tail risk and the equity premium. In contrast, macro risk is only weakly related to future consumption growth, meaning that our estimates reproduce the well-known disconnect between the equity premium and consumption. Finally, these results hold when we construct macro risk excluding asset-price predictors. We next ask if rare disaster models help rationalize the equity premium puzzle and other patterns we observe in the data. Following the Mehra and Prescott(1985) approach, we calibrate the stochastic process for consumption dynamics, derive the process for prices, and compare those prices to their empirical counterparts. A benefit of our approach is that we can work with estimated consumption dynamics that exclude asset-price predictors, meaning that consumption parameters are not reverse-engineered to fit the asset pricing data. We consider a rare disaster model similar to Wachter(2013), in which agents have recur- sive preferences. Consumption growth follows an exogenous stream, which is subject to rare disasters that occur with a time-varying probability.2 The model is in discrete-time and is of
2Another strand of research maintains a constant disaster probability but assumes that the representative agent learns about the model parameters or states (e.g., Weitzman, 2007; Koulovatianos and Wieland, 2011; Du and Elkamhi, 2012; Orlik and Veldkamp, 2014; Johannes et al., 2016). Martin(2013) shows that constant disaster risk spreads across assets in a multiple-tree economy and leads to endogenous risk premia dynamics.
2 the exponential affine type so that it can be solved with standard techniques and yields simple, closed-form solutions. We use this model as a laboratory to assess both the qualitative and quantitative effects of our measure of time-varying disaster probability—that is, our model’s only state variable. The model generates a high and volatile equity premium and a low risk- free rate under conservative preferences. It can also reproduce both the predictability of stock returns and the lack of predictability of consumption growth by asset prices that we observe in the data. Alternative model specifications support the idea that time-varying disaster prob- ability is a priced state-variable, responsible for a sizable component of the equity premium and its dynamics—even when its endogenous correlation with the D/P ratio matches that in actual data. Taken together, our findings suggest macroeconomic tail risk can rationalize the equity premium and risk-free rate puzzles, the excess volatility puzzle, and the predictability of aggregate stock market returns by the dividend-price ratio. Our paper is related to a large body of work in asset pricing and macroeconomics that is concerned with measuring the variability of output growth (e.g., DeLong and Summers, 1986; Stock and Watson, 2002; Schorfheide et al., 2018) and macroeconomic uncertainty (e.g., Orlik and Veldkamp, 2014; Jurado et al., 2015; Nakamura et al., 2017). Giglio et al.(2016) and Adrian et al.(2019) relate the conditional distribution of GDP growth to measures of financial market distress. In a seminal paper, Barro(2006) documented that in international consumption data, disaster risk is compatible with a high equity premium. Barro further conjectured that variation in disaster risk could rationalize a volatile equity premium. We provide evidence supporting Barro’s conjecture. A number of recent works provide indirect measures of macroeconomic tail risk. Berkman et al.(2011) use the number and severity of international political crises to proxy for time-varying disaster risk, Colacito et al.(2016) use survey data, and Manela and Moreira (2017) construct a volatility index using front-page articles of the Wall Street Journal, which they relate to disaster concerns. These papers rely on the assumption that the proposed proxy adequately reflects macroeconomic concerns. In contrast, our approach takes candidate proxies as input and measures tail risk by projecting them on future tail events. The fact that our risk estimate varies over time is the direct consequence that these candidate proxies forecast future macroeconomic crises. Another suitable vehicle for estimating tail risk is option prices. Our macro risk measure corresponds to the probability of a macroeconomic crisis under rational expectation, provided our predictor set spans the information set of economic agents. Interpreting option prices, in contrast, does not need assumptions about investors’ information set. Both Siriwardane(2015) and Barro and Liao(2019) back out the probability of a macroeconomic crisis, the former under
3 the risk-neutral measure and the latter under the physical measure, over the shorter period over which option data is available. Doing so requires assumptions about investors’ preferences and the joint behavior of the stock markets and macroeconomic outcomes. In practice, the option- based estimates of Siriwardane(2015) and Barro and Liao(2019) are tightly linked to volatility indices such as the VIX. Their estimates can thus be cast within our predictive framework as one among many candidate predictors for future crises. We find that stock volatility strongly forecasts macroeconomic crises but that many other variables have incremental forecasting power. The rest of this paper is organized as follows. SectionI presents our data and methodology. SectionII documents that large macroeconomic crises are forecastable. SectionIII presents estimated macro risk and studies the relationship between macro risk and variables such as stock returns and macroeconomic growth. SectionIV calibrates a rare disaster model using macro risk dynamics. We conclude in SectionV. An Online Appendix contains additional results and proofs.
I. Methodology and Data
We begin by presenting our econometric framework. We are interested in quantifying macroe- conomic tail risk in country i = 1,...,N, denoted by πi,t, and defined as the year t probability of a macroeconomic crisis at time t + 1,
πi,t ≡ Pr(Crisisi,t+1 = 1|Ii,t), (1)
where the probability Pr(.|Ii,t) is taken with respect to information Ii,t available to economic agents at time t. We define a macroeconomic crisis as a severe decline in consumption or output during a given year. A country i experiences a macroeconomic crisis in time t if the log growth rate in country i, ∆ci,t, falls by k standard deviations (SD) from its long-term growth path:
1, if ∆ci,t < mean(∆ci,t) − k × SD(∆ci,t). Crisisi,t = (2) 0, otherwise.
This modeling choice conforms with the common approach in the rare disasters literature to define tail events as cumulative declines in consumption (or GDP) that exceed a fixed cutoff value. An alternative choice, pursued in Adrian et al.(2019), consists in constructing crisis
4 probabilities from quantile regressions. We show in the Online Appendix that this approach yields similar tail risk estimates. The fixed-cutoff assumption amounts to treating the long-term growth rate and volatility in normal times as constant parameters, a common assumption in the rare disasters literature.
Variation in πi,t thus summarizes movements in recession risk, which depends on both the level, volatility, but also on higher moments of the growth process. Our baseline crisis definition departs from the rare disasters literature in that macroeconomic crises are one-year events. Although it is natural to think of macroeconomic crises as events that unfold over several years, measuring macroeconomic tail risk in calendar time is better suited to our forecasting framework.3 We nevertheless explore crisis probabilities using crises identified in Barro and Urs´ua(2008) in Section III.B.
A. Empirical implementation
We need to introduce a few assumptions to operationalize the approach in Eq. (2) and (3). We are interested in severe and rare crises, which are approximately comparable across countries. Our baseline specification thus sets the crisis cutoff k = 2 in Eq. (2). We compute the long-term growth rate and standard deviation on a country by country basis. This ensures that over the long run, crises are approximately equally rare in the cross section. For standard deviations to reflect macroeconomic volatility in good times, we use series winsorized at the 2.5% level in both tails. Further, as noted in, e.g., Nakamura et al.(2013), the series assembled by Barro and Urs´ua(2008) are in many countries much less volatile after Word War II. To a large extent, this fall in volatility likely reflects changes in national accounts measurement around this time (Romer, 1986; Balke and Gordon, 1989). We thus identify macroeconomic crises using distinct standard deviations for the pre- and post-WW2 samples in our baseline specification.4 We find that this approach identifies events that largely overlap with the ones studied in the rare disasters literature. Later we present macro risk estimates based on cutoffs of 1.5, 2.5, and 3 standard deviations, as well as based on the crises identified in Barro and Urs´ua(2008). Our baseline specification relies on consumption series because asset pricing theory links the equity premium to aggregate consumption, but we also produce estimates based on GDP data. We also present estimates based on crises identified using standard deviations that remain fixed after WW2. 3Defining crises as one-year events is also consistent with the assumption in the model in SectionIV that macroeconomic disasters occur instantaneously. Our modeling approach is thus immune to the measurement issues highlighted by Constantinides(2008), Donaldson and Mehra(2008), and Julliard and Ghosh(2012). 4Some countries have very few observations in the prewar period. We use the full-sample standard deviation whenever we have less than 25 years of prewar data.
5 A common concern in the rare disaster literature is that macroeconomic crises are so rare that even pinning down the unconditional crisis probability poses a challenge. We gain traction by using a broad array of predictive variables. We posit a model in which the unobserved quantity of interest, πi,t, is a function of the information available at year t. This information can be summarized by the vector Xi,t, i.e., πi,t = f(Xi,t) for some function f. In our baseline specification, we postulate that f takes the form of a standard normal distribution (i.e., a probit model). Eq. (3) therefore becomes: